Recent international study of teacher work has highlighted its complex nature and its shared ecological demands for classroom instruction. In Japan and Australia, special educators have worked with groups of students including those with autistic spectrum disorder (ASD) and with groups of teachers. It has appeared that, despite considerable ecological similarity in the practices of special educators, different approaches have shaped their work with groups in both countries. The most scientifically proven category of practices for teaching students with ASD has been the skill based practices associated with applied behaviour analysis, which have shaped classroom instruction of Australian special educators. In contrast, an interpersonal category of teacher practice for students with ASD has involved a longer-term naturalistic process of interaction and instruction, harder to quantify and presently classified as having an insufficient evidence base. Japanese teachers' classroom instruction and collaborative lesson study with colleagues, which have been associated with this category of interpersonal practices, have provided a natural laboratory to describe the classroom involvement of students with ASD in their daily group work. A cross-cultural case study was designed to investigate the different meaning and purpose of using "group" to teach students and to interact with colleagues in an elementary setting in Japan and Australia respectively. This discussion of preliminary findings from the Japanese setting will be focused on collaborative use of lesson study in their work.